The present invention relates to an eyeglass lens processing apparatus and a method of processing an eyeglass lens.
A periphery of a lens held by lens chucks is processed by a processing tool such as a grindstone, in an eyeglass lens processing apparatus so that the processed lens is fitted to a rim of an eyeglass frame. When a glass lens, a plastic lens, or the like is processed in the above-mentioned apparatus, water is supplied to cool a portion being processed of the lens and to remove scraps of the lens. A circulation method using a water storage tank and a pump has been used as a method of supplying the water. In addition, a waterworks direct-connection method for directly supplying the water from a waterworks is used as the method of supplying the water.
However, when a plurality of lenses is continuously processed in the circulation method, the temperature of the water discharged into the water storage tank rises. For this reason, the water is supplied again while the water is not sufficiently cooled. When the temperature of the water to be supplied is high, the lens is thermally expanded during the processing. Even though the lens is processed using processing data, the lens contracts after the processing. As a result, the size of the processed lens is decreased. In particular, when the processing is performed to form a bevel on the circumferential surface (edge surface) of the lens, it is difficult to fit the processed lens to the rim.
In the related art, the lens is processed so as to have a slight large size and adjustment finishing is then performed to solve the above-mentioned problem. Alternatively, a cooling agent is input to the water storage tank, the temperature rise of the water is suppressed by a cooling unit, or the water in the water storage tank is replaced during the continuous processing. However, the adjustment finishing is troublesome, and processing quality is different for each operator. In addition, the method of suppressing the temperature rise of the water causes much processing cost, and is troublesome.
Meanwhile, the temperature rise of the water in the waterworks direct-connection method is smaller than that in the circulation method. However, since the temperature of the water is changed in seasons, the same problem occurs.